Abstract

The first observations of the kronian equivalent of hot flow anomalies (HFAs) are presented. Using magnetic field and plasma data we discuss two events that were observed upstream of Saturn's bow shock during the first two orbits of the Cassini spacecraft. We suggest that these events result from the interaction between interplanetary current sheets and the shock surface. This same interaction is responsible for HFAs at the terrestrial bow shock. Calculations of electron temperature reveal an increase by a factor of approximately two for the first event, which is less than for terrestrial HFAs where the increase is by approximately an order of magnitude. In contrast to terrestrial HFAs we find that these events are associated with density enhancement rather than reduction. Estimates of the total pressure for the first event imply that the central region is expanding.